Question

Subtract:

6x³ − 7x² + 5x − 3 from 4 − 5x + 6x² − 8x³

Answer 1

Change the sign of the term of the expression that is to be subtracted and then add.

Term to be subtracted = 6x³ − 7x² + 5x − 3
 Changing the sign of each term of the expression gives -6x³ + 7x² - 5x + 3.
On adding:
(4 − 5x + 6x² − 8x³)+(-6x³ + 7x² - 5x + 3) = 4 − 5x + 6x² − 8x³-6x³ + 7x² - 5x + 3
= (-8-6)x³ +(6+7)x² +(-5- 5)x + 7
= -14x³ + 13x² - 10x + 7